The 90-ton rocket launched at 6:39 p.m. EDT, but 81 seconds into the launch, the U.S. detected a substantially larger than expected flare and by ten minutes after launch, the rocket was no longer on several radar screens, U.S. officials said.

According to a statement from U.S. Northern Command and NORAD, the missile was tracked on a southerly launch over the Yellow Sea.

"Initial indications are that the first stage of the missile fell into the sea 165 km west of Seoul, South Korea," the statement said. "The remaining stages were assessed to have failed and no debris fell on land. At no time were the missile or the resultant debris a threat."

White House Press Secretary Jay Carney said in a statement that despite the failed launch, "North Korea's provocative action threatens regional security, violates international law and contravenes its own recent commitments. "

Carney added "any missile activity by North Korea is of concern to the international community. The United States remains vigilant in the face of North Korean provocations, and is fully committed to the security our allies in the region."

President Obama has been prepared to "engage constructively with North Korea," he said in the statement. "However, he has also insisted that North Korea live up to its own commitments, adhere to its international obligations and deal peacefully with its neighbors.'

Had the launch been successful, the rocket's third stage was expected to burn up in the atmosphere about ten minutes after launch, with debris falling north of Australia.

After the launch, South Korea's president Lee Myung Bak called an emergency cabinet meeting of his government.

Japanese officials, meanwhile, rushed to hold an emergency security meeting just after the launch. Japanese Defense minister Naoki Tanaka said no PAC3 missile batteries were used in the launch and the rocket was, "No threat to Japan."

The rocket was launched from the Sohae Satellite Launching Station in the northern part of the country, near North Korea's border with China.

Anticipation of the missile launch began in March when the Communist nation announced a five-day window for launching a satellite, which began on Wednesday.

The show of muscle put the region on edge, but Donald Gregg, former U.S. Ambassador to South Korea from 1989-1993 and an ABC News consultant, said he believed it was new leader Kim Jong Un's way of asserting his power.

"The main audience for this missile is internal not external," Gregg said before the launch. "This is [Kim Jong Un's] way of demonstrating to the people of North Korea he is in charge and his country is capable of high tech things. It is a manifestation of his power."

North Korea claimed the planned rocket launch was just a satellite called Shining Star, which was being launched into orbit to celebrate the 100th anniversary of the birth of the regime's founder, Kim Il Sung.

Experts did not doubt the possibility of a satellite being attached to the rocket, but believed the satellite to be a cover in order to test a long-range missile.

A nuclear test may soon follow, experts say. Large amounts of dirt and ground cover are being moved at one of North Korea's nuclear sites, which experts believe indicates the North Koreans plan to test a nuclear device.
Even more alarming is that officials believe that, unlike the first two nuclear tests North Korea conducted with plutonium, this one could be a uranium device, which would indicate a secret uranium production facility.

Gregg said the U.S. likely would not be a direct target of a potentially nuclear North Korea.

"The North Korea nuclear capability is not ever designed to be used against us. They know anything used against us would result in a catastrophic response," he said.

The rocket launch defies two United Nations Security Council resolutions that prohibit North Korea from testing ballistic missiles. It also breaks a promise North Korean leaders made to U.S. leaders in Beijing at the end of February.

The regime had promised to suspend nuclear missile tests, uranium enrichment and long-range missile launches in exchange for food aid from the United States.